20" Muzzle velocities and powder recomendation

[Kevlars]

I recently cut down my custom .308 rifle from 24" to 20" and had it threaded for a AWC ThunderTrap TI. I wanted to know what muzzle velocities I should expect with the suppressor. I am using Varget 44.5 grains with Federal 210M primers, with Lapua brass and SMK 175's. My chrony is showing about 2550 as an average, does that sound right?

Currently I shoot only at the range (100, 200 yards) but I occasionally get out to the courses that shoot 800 Yards +

Should I try another powder to get more MV, any recomendations ?

Just trying to plug into some of the knowledge base here on the hide.

 

[bm11]

Re: 20" Muzzle velocities and powder recomendation

That sounds exactly right for muzzle velocity out of a 20" with 44.5 grains of Varget. What elevation do you live at? I imagine that you will be good to go with that load, as long as it shoots, unless you have some really unrealistic expectations of how far you can shoot that load.

 

[pyplynr]

Re: 20" Muzzle velocities and powder recomendation

That is almost the same load with my 20"bbl. Only difference is that I'm using a 178gr Amax and CCI BR2 primers. I average 2550 at 1300' asl.

 

[Kevlars]

Re: 20" Muzzle velocities and powder recomendation

oops forgot to give you that ..

I live at about 1800 feet in Arizona... my expectations are 800 yards at a minimum ... I would like 1000 but I know that it can get "weird" at 1000 and I know it is a low percentage shot. So 800 for sure. I just want to make sure that I am not "missing the boat" and I should try a new powder like XBR.

 

[RobG]

Re: 20" Muzzle velocities and powder recomendation

I get 2600ish with 45 g of Varget from my LTR with the same bullet. Accuracy sucks however. Gonna be loading some MR 2000 with hopefully better results.

 

[BirdmanOz]

Re: 20" Muzzle velocities and powder recomendation

I get 2440 FPS from 41.3 of H4895 (ADI 2206H) with 168 SMK at 2.8 OAL. Its a 20 inch SPS remington. I think this powder burns slightly faster than varget. I'm told its better for shorter barrel. Max load recommended is something like 43. Min is 41 so im working my way up. I reckon 2600 to 2650 at top end of this load range.

PS great accuracy with this but needs to speed up to extend to max ranges.

 

[Da-Law-Dawg]

Re: 20" Muzzle velocities and powder recomendation

MV sounds spot on with your load. Running a 168 Amax with 44.0gr of Varget averaged 2571fps out of an 18.5" tube for me.

You might try the XBR as stated. I got the nod for it from a guy running it recently. I have a new custom with a 22" Rock barrel and have Varget and XBR loaded for it. Will get you some numbers on it as soon as I get her to the range.

 

[blklabs]

Re: 20" Muzzle velocities and powder recomendation

You should be fine for 800 with 2550 and the 175 SMK. Generally speaking you need 2600 or over for 1k at sea level. Given your altitude and how close you are to 2600, I would say that on days with a high DA you can make it to 1k. If you want a reliable 1k load you will need to get over 2600.

 

[Kevlars]

Re: 20" Muzzle velocities and powder recomendation

Ok ... sounds like my Chrony is telling me the truth ...realistically I am shooting to 800 yards. If I want reliable accuracy at 1000 then it will be time to get a .338.

Thanks all for validating what I am seeing.

 

[Rob01]

Re: 20" Muzzle velocities and powder recomendation

That sounds slow especially out of a custom barrel. My last .308 barrel was 20" and I was getting about 2690fps from 44.4grns of Varget in Lapua cases and 45grns in Win cases with 178 AMAXs.

 

[chansen49]

Re: 20" Muzzle velocities and powder recomendation



Im getting 2680 from FGMM 168 outta my 20" at 5000 feet

 

[McLarenross]

Re: 20" Muzzle velocities and powder recomendation

I'm getting 2670 over my chrony outta my 20" factory barrel 700 with 178 a-max, 46.3gr RL-15, in winchester cases and wolf LRM primer loaded to 2.940" oal. That's at ~500' asl.

 

[TonyAngel]

Re: 20" Muzzle velocities and powder recomendation

Yeah, that sounds low to me too, for a custom build. Stock barrels usually get you lower velocities due to the loose chamber and long throat, but a custom barrel (if done right) should get you better velocities.

My 22" Kriger barreled .308 gets me over 2600 with 43gr. of RL15 (which is pretty close to Varget) with a 175 SMK. 44gr of Varget with a 168gr SMK gets me something just over 2700.

What do you mean by "custom"? If it's a stock barrel that you've had work done to, then your number sounds about right. If I ran your load through any of my rifles, I wouldn't be able to get the bolt open.

 

[Kevlars]

Re: 20" Muzzle velocities and powder recomendation

It is a custom rifle made by "Tactical Rifles" I am currently at 1800 feet. I ran the numebers through QL and they came up the same so I am confident that the fps of 2550 for 44.5 of varget with Lapua brass and Federal 210m primers is correct with a 20 inch barrel.

 

[HillbillyfromAL]

Re: 20" Muzzle velocities and powder recomendation

I'm at 7,000ft and 44.4gr of Varget gives me 2650 out of my factory barrel. However I used a moly coat to burnish it not sure if that had much to do with it. If you want to check it out it's made by Sentry Solutions, I used the smooth coat and BP2000 in conjunction with each other. I can't remember exactly who it was, I want to say Shilen, but there was a good write up on how to properly use moly. It may be just thing to give you a little more speed. I hope that your rifle wasn't from your "...." dot net.

 

[TonyAngel]

Re: 20" Muzzle velocities and powder recomendation

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">t is a custom rifle made by "Tactical Rifles" I am currently at 1800 feet. I ran the numebers through QL and they came up the same so I am confident that the fps of 2550 for 44.5 of varget with Lapua brass and Federal 210m primers is correct with a 20 inch barrel. </div></div>

I guess you just answered your own question. You number still seem low to me for a "custom" rifle. I'm getting the numbers that I posted above at sea level too.

 

[Kevlars]

Re: 20" Muzzle velocities and powder recomendation

Thank you Tony I will run your numbers in QL tonight and see what I get.

When I adjusted the numbers correctly in QL it was displaying exactly what I was getting via my Chronographer. I am not using Molly or anything like that.

I will let you know what I find out.

Thanks

 

[dmdakota]

Re: 20" Muzzle velocities and powder recomendation

175 smk
win brass
cci br2
45.8 varget-----new lot is slow,down about 60fps
2.81 oal
2619fps
factory barrel sps tactical
showing small ejector swipes

old lot of varget same load 2680fps

 

[terrance250]

Re: 20" Muzzle velocities and powder recomendation

20" SPS
175 SMK
45gr Varget
Fed 210M
Win Brass
2610fps

 

[tt350z]

Re: 20" Muzzle velocities and powder recomendation

Out of my 20'' Bartlein, measured from muzzle to bolt face.

1x fired American Eagle 7.62x51 MIA brass
uniformed flash hole
SMK 175 gr
RL15
CCI 200 primer
.010'' into the lands
Ogive length 2.205''
OAL apprx 2.775ish''

44.5 gr of RL15

Competition Electronics Pro Chrono Digital 10' from muzzle
2743 FPS
2749 FPS
2737 FPS
2721 FPS
2721 FPS

Avg: 2734 FPS

This is what my brass looks like.

 

[Kevlars]

Re: 20" Muzzle velocities and powder recomendation

Yup you guys were right ... I re-chrony'd and measured and found with 44.5 of Varget I was getting 2676 out of my 20 inch barrel (did say bullets lol)

 

[blklabs]

Re: 20" Muzzle velocities and powder recomendation

Well you now have a load capable of 1000 yards, enjoy it. On a side not a 20 inch bullet is pretty long, lol.

 

[Kevlars]

Re: 20" Muzzle velocities and powder recomendation

LMAO ...Ya I just changed it ... thoes would be pretty long... Hell I would melt them down for the copper....

thanks

 

[winxp_man]

Re: 20" Muzzle velocities and powder recomendation

Few people posting the ASL it has nothing to do with muzzle velocity. It only helps when shooting long range and there is the need to know the drop. 2550 is what mine does with Winchester cases 4-6 times reloads. What I have tried recently was some RL-15 44.0gr and got 2620 super easy with about .6-.5 accuracy out of my SPS Tac. There was no pressure signs at all. I will be trying some some XBR powder really soon and see how it does.



Aron-

 

[mark stapleton]

Re: 20" Muzzle velocities and powder recomendation

That sounds about right , most velocities on loading data are from a 24 " brl, Hodgdon give a fps of 2690 so a loss of 140 is believable . Varget will produce faster sppeeds than most.
Depending on your twist if you go to a 155 Sierra Match King
or Hornady Amax rather than the 175 you will pick up a couple of hundred feet per second . These are a very common and popular projectile for target shooting with the 308.Somewhere between 46 and 47 grains of Varget , I use 46.4 but work up to that .cheers